A synchronizing device, for a vehicle gearbox, with a synchronizer body which can be mounted rotationally fixedly on an axial shaft, and a shift sleeve which is connected rotationally fixedly to the synchronizer body and can be moved axially along an outer periphery of the synchronizer body and which, to perform a synchronizing process, can be brought from a neutral position into rotationally fixed engagement in a first shift phase with an axially displaceable synchronizer ring and in a second shift phase with a clutch body adjacent to the synchronizer ring. During the first shift phase, the synchronizer ring can be moved in the direction of the adjacent clutch body by the shift sleeve using pressure pads arranged axially displaceably in the synchronizer body, and hence can be brought into frictional engagement with the adjacent clutch body for the purpose of pre-synchronization.

A transmission includes a primary gear including primary teeth, each having a primary surface; a secondary gear including secondary teeth; an intermediate gear including intermediate teeth, each comprising a primary intermediate part having a primary intermediate surface and a secondary intermediate part having a secondary intermediate surface, where the primary intermediate part is axially offset from the secondary intermediate part. The intermediate gear is axially displaceable to an engaged position. The primary surface contacts the primary intermediate surface in a contact region and the secondary intermediate surface contacts one of the secondary teeth. In the engaged position, one primary tooth and one intermediate tooth form an overlap, radially inside the contact region, for preventing the intermediate gear from being displaced from the engaged position to a disengaged position.

A synchronizer of a transmission may include a lower key disposed slidable in a radial direction of a hub; an upper key disposed at an external side of the lower key in the radial direction to be slidable in an axial direction of the hub; a sleeve disposed at an external side of the hub to slide the upper key in the axial direction while being slid in the axial direction thereof, pressing the upper key toward a synchronizer ring; a key spring disposed between the lower key and the hub to press the lower key and the upper key toward an internal surface of the sleeve; and a displacement converting device converting relative displacement generated in a circumferential direction of the hub between the upper key and the lower key into relative displacement of the upper key in axial direction toward the synchronizer ring with respect to the lower key.

A transmission synchronizer apparatus may include a sleeve coupled to an external peripheral surface of a hub gear while moving axially, and clutch gears disposed at both sides of the hub gear, each selectively synchronizing and engaging with the sleeve according to the axial movement of the sleeve, wherein the transmission synchronizer includes a plurality of main sleeve teeth protruding inwardly from an internal peripheral surface of the sleeve while being distanced from one another, and an auxiliary sleeve tooth protruding inwardly from the internal peripheral surface of the sleeve while protruding from one side of each of the main sleeve teeth to have a height lower than the main sleeve tooth.

A synchronizer unit for a manual transmission, in particular of a motor vehicle, has a hub which is adapted to be connected to a gear shaft for joint rotation therewith and includes a circumferentially continuous external toothing, a sliding sleeve which is received on the external toothing of the hub for displacement in the axial direction, but so as to be coupled in the circumferential direction to prevent relative rotation, at least one synchronizer ring which includes a preferably cone-shaped friction surface for friction coupling of the synchronizer ring to a speed change gear of the manual transmission and is adapted to be actuated by the sliding sleeve, and a spring ring which is arranged at an axial side of the external toothing of the hub and is configured to lock the sliding sleeve in a neutral position. The spring ring rests against a face side of the sliding sleeve and being operatively arranged between the sliding sleeve and the synchronizer ring.

A heterogeneous powder molded body may include respective powder processed parts formed of different powders, the heterogeneous powder molded body being formed by a forming machine including a die, a lower forming module located under the die to form a lower part of a molded body to be manufactured, and an upper forming module located above the die to form an upper part of the molded body to be manufactured, in which when each of the different powders is input onto the die to form the molded body, the die ascends and thus a filling time of each input powder is secured.

A gearbox (BV) comprises a secondary shaft (AS) provided with a synchromesh (SB) comprising a flange (FL) comprising a sub-hub (SM) fixedly secured to the secondary shaft (AS) and provided with external splines (CE3), a hub (MO) comprising internal splines (CI1) collaborating with the external splines (CE3) of the sub-hub (SM) to allow translational movement with respect to the latter (SM), and a sleeve (MA) that can undergo a translational movement with respect to the hub (MO) so that the internal splines (CI2) thereof are closely coupled to dogs (CR) of an idling pinion (PF1). This translational movement of the hub (MO) with respect to the sub-hub (SM) guarantees close coupling of the internal splines (CI2) of the sleeve (MA) with the dogs (CR) with a minimal margin for translation, irrespective of dimensional variations in the manufacture of the sleeve (MA) and idling pinion (PF1).

A shift device includes an output shaft, a hub, a speed gear, a sleeve, a synchronizer ring, lever members, and a spring. The lever members have torque receiving portions contactable with projections of the synchronizer ring to receive friction torque from the projections. Contact positions of the torque receiving portions and the projections in a synchronization operation are set at a hub side of the lever members and an axial-directional distance between points of support and the contact positions is less than a thickness of the lever member.

A synchronizer hub for vehicles and a method for manufacturing the same forms an inner spline and an outer spline of a transmission synchronizer hub for vehicles by using different materials.

The synchronizer hub may be manufactured by filling inner powders for forming the inner spline, molding the inner spline, filling outer powders for forming the outer spline, molding the outer spline, separating the double molded object obtained by integrally forming the inner spline and the outer spline from a mold, and performing sintering, post-processing, and high-frequency heating processes.

A gearbox (BV) comprises a secondary shaft (AS) provided with a synchromesh (SB) comprising a flange (FL) comprising a sub-hub (SM) fixedly secured to the secondary shaft (AS) and provided with external splines (CE3), a hub (MO) comprising internal splines (CI1) collaborating with the external splines (CE3) of the sub-hub (SM) to allow translational movement with respect to the latter (SM), and a sleeve (MA) that can undergo a translational movement with respect to the hub (MO) so that the internal splines (CI2) thereof are closely coupled to dogs (CR) of an idling pinion (PF1). This translational movement of the hub (MO) with respect to the sub-hub (SM) guarantees close coupling of the internal splines (CI2) of the sleeve (MA) with the dogs (CR) with a minimal margin for translation, irrespective of dimensional variations in the manufacture of the sleeve (MA) and idling pinion (PF1).